I have a Dataset which is LRECL=5400. There are some records in the DSN which is having value as PQ or NF on 3847th byte. I need to replace those value into QC or NL respectively. I need the sample JCL with exact syntax how to do that using DFSORT.

I have tried the First and Third method. The first method did not work. I got some error. i think that error because of the DFOSRT version which i am using in my mainframe. the third method worked. I did not try the second method.

That's correct - the error message indicates you do not have z/OS DFSORT V1R5 PTF UK90013 (July, 2008) installed. In order FINDREP to work, you need this PTF. You might like to ask your System Programmer to install it (it's free, as you are a DFSORT user).

Actually, ask your System Programmer to install z/OS DFSORT V1R5 PTF UK51706 (Nov, 2009). That will get you all of the latest DFSORT functions.
For more information on the functions available with various DFSORT PTFs, see: